The suggested maintenance = gritting doesn't seem like a goo idea to me. This makes multiple maintenance options harder to parse for, and doesn't really capture what's going on. Is this actually needed? How about gritting=yes, but only used if the priority isn't known.
Rather than gritting=priority_n how about using gritting:priority=n and also adding gritting:operator=* and possibly gritting:rout_ref=* too. The operator will become important if different councils are operating on different policies on a given day, and it's not just a matter of looking at borders, since some trunk roads and motorways are handled centrally by the Highways Authority or their contractors.
-- Rjw62 12:46, 19 January 2010 (UTC)